RE 1-22 Flashcards
What separates the upper and lower airway?
cricoid cartilage
Upper airway?
nose, mouth, pharynx, hypopharynx, larynx
Lower airway?
trachea, bronchi, bronchioles, terminal bronchioles, respiratory bronchioles, alveoli
The auditory (eustachian) tubes and the adenoids are found in what part of the airway?
nasopharynx
efferent response through the vagus nerve results in what?
gag reflex-the muscles of the parynx elevate and constrict
Why is the recurrent laryngeal nerve named as such?
because it loops around other structures
The right RLN loops around what structure?
brachiocephalic artery
The left RLN loops around what structure?
the aorta
Traction on the RLN can lead to what
nerve injury, hoarseness
Traction on the RLN may be caused by what pathologic conditions?
Mitral stenosis, Disecting aortic arch aneurysms
Acute RLN may progress to what?
respiratory distress, death
Patients with chronic bilateral RLN injury may sound how?
gruff or husky speach
Injury to what nerve is least likely to cause respiratory distress
SLN
4 functions of the larynx
- protection to the lower airway from aspiration
- patency btw the hypopharynx & trachea
- protective gag and cough reflexes
- phonation
What connect the thryoid cartilage to the hyoid bone?
thryhyoid fascia and muscles of the larynx
What type of cartilage is the epiglottis?
single leaf like
The space between the inferior edge of the epiglottis and the true vocal cords is known as what?
inferior vallecula
The space between the epiglottis and the base of the tongue is known as what?
superior vallecula
Intrinsic muscles of the larynx control ?
tension of the vocal cords
opening and closing of the glottis
Extrinsic muscles of the larynx control
connect the larynx, hyoid bone, and neighboring structures
adjust the position of the trachea during phonation, breathing, and swallowing
Muscles that elevate the larynx?
stylohyoid digastric mylohyoid genihyoid stylopharyngeus thyrohyoid
Muscles that depress the larynx?
omohyoid
sternohyoid
sternothryoid
Parasympathetic innervation of the tracheobronchial trees is provided by?
Vagus nerve
Sympathetic innervation of the tracheobronchial trees is provided by?
1-5 thoracic ganglia
The posterior side of the trachea is membranous for what reason?
to accomodate the esophagus during swalloing
The cartilaginous rings continue until the bronchi reach?
- 6-0.8 mm in size
* cartilage disappears and bronchi are termed bronchioles
The point at which the cartilage disappears and the bronchi begin is termed?
bronchioles
What is the function of the bronchi
provide humidification and warming of inspired air
True or false-individual airway assessment is an adequate predictor of airway difficulty.
False-individual = poor,
Use of Mult airway assessments = good
Murphy & Walls described the four dimensions of difficulty, what are they?
- BMV
- DL w/ direct tracheal intubation
- SGA
- Invasive airway placement
History of difficult airway is a sign of what?
current difficulty history
If unable to BMV after OPA placement what is another technique to ventilation the patient?
two handed BMV
What is the incidence of impossible BMV
0.15%
Signs of inadequate ventilation during BMV
- minimal to no chest rise
- inadequate or deficient exhaled CO2
- reduced/absent breath sounds
- decreasing 02 sat ,92%
Hallmarks signs of upper airway obstruction in unanesthetized patient?
hoarse or muffled voice
difficulty swallowing secretions
stridor
dyspnea
What are two ominous signs of respiratory obstruction that indicate a 50% decrease in airway circumference from normal or a diameter reduced to 4.5 mm or less?
stridor and dyspnea
Hallmarks signs of lower airway obstruction in unanesthetized patient?
high peak airway pressures
low tidal volumes
impaired ventilation
Patients w/ OSA may be challenging when performing what airway maneuver?
BMV
What makes patients who are pregnant difficult to ventilate?
gravid uterus compressing the lungs creates elevated airway resistance.
Examples of upper airway obstruction?
trauma, burns, congenital, abscess, ludwigs angina, OSA, tongue, angio edema, foreign body, epiglottitis, laryngospasm
Examples of lower airway obstruction
angioedema, ARDS, COPD, asthma, bronchospasm, pulmonary edema, obesity, prego
DTI
direct tracheal intubation
- process of placing ETT into the trachea
DL = process of airway instrumentation with laryngoscope to acquire a direct line of site with the laryngeal opening
What is the incidence of difficult tracheal intubation?
1.5-8.5%
What is the incidence of failed tracheal intubation?
0.3-0.5%
What two techniques most accurately predict difficult intubation?
Mallampati & TMD
What assessments best predict difficult laryngoscopy?
Mallampati, TMD, interincissor gap
What position should the patient be in when Mallampati is being performed?
sitting upright, extend the neck, open the mouth as much as possible, and protrude the tongue and avoid phonation
What is the incidence of visualizaiton of any part of the epiglottis on mouth opening?
1.2%
Mallampiti classification, decreased TMD, and limited interincisor opening are strong predictors of?
Difficult larygoscopy and intubation troubles
Cormack and Lehane III and IV correlate with what?
difficult intubation
TMD is a predictor of what?
the space in which the tongue can be displaced during DL to improve the direct line of site with the glottic opening
What is mandibular hypoplasia?
Condition in which the tongue does not fit into the thyromental space.
True or false-The greater the TMD the easier the intubation
False-TMD greater than 9 cm may also indicate a potentially difficult airway d/t large hypopharyngeal tongue, caudal larynx, and longer mandibulohyoid distance (MHD)
What does MHD measure?
the distace form the angle of the mandible to the hyoid bone (usually via radiograph)
Long TMD and MHD may indicate what regarding glottic opening
caudal
In assessing the position of the larynx with the 3-3-2 model, more than two fingerbreadths would inidcate the larynx position is? less than two fingerbreadths would indicate?
more than two -larynx may be positioned down the neck
less than two - larynx tucked under the base of the tongue, anterior larynx
Normal SMD =?cm
> 12cm
*<12.5cm predicts difficult DTI (considered poor indicator even when used with Mult other assessments)
How big is the flange on a laryngoscope blade?
2 cm
Normal mouth opening?
2-3 FB or 4 cm
Buck teeth may increase the risk of ?
dental damage
Degree of neck flexion and extension decreases by what percent from 16 years of age to 75 years of age?
20%
Neck flexion and extension varies from?
90-165 degrees
What joint provides the highest degree of neck mobility?
AO
What happens when extension is reduced to 23 degrees?
visualization may be difficult
The upper lip bite test is also known as?
ULBT-upper lip bite test= mandibular protrusion test
*valuable assessment tool for difficult airway: problematic oral airway placement, noneffective relief of soft tissue obstruction from poor mandibular mvmt, diff introducing blade into mouth, & obstructive view of glottic opening caused by maldisplacement of the tongue.
What is the purpose of the ULBT?
Assess the mobility of the patients temporomandibular joint function and forward subluxation of the jaw (and assess patients maxillary incissor distance)
Class III ULBT indicates?
lower incisors cannot be moved in line with the upper incisors and cannot bite the upper lip
ULBT is unreliable in what patient population?
edentulous patients
ULBT is best used with what other tests?
increased neck circumference and history of snoring or Modified Mallampati Classification
What 2 factors may make SGA difficult (assessment, condition)
small inter-incisor gap & reductions in atlanto-occipital (AO) joint mvmt (RA or AS).
Obstruction at the level of ______, ______, or below can reduce or completely block ventilation from a SGA device (LMA).
Larynx, Trachea, or Below
When pressures reach _____cm H20 or higher ventilated gases through an SGA device could overcome __________ pressures causing inflation of the stomach, increased in intragastric pressure, & possible risk of vomiting & pulmonary aspiration
25cm H20
esophageal sphincter pressures
What is the absolute contraindication for placement of an emergency cricothyrotomy?
There is NO absolute contraindication
procedures that make performing cricothyrotomy more difficult=
SHORT–> surgery, hematoma, obesity, radiation, tumors/trauma.
CT scans are the gold standard for ruling out what possible complication?
fractures of the cervical spine
CT scans are capable of imaging _____ & ____ whereas MRI can only image _____
soft tissue and bone, soft tissue
Effective preoxygenation can theoretically provide oxygen to the blood for how long in a healthy individual?
12 minutes